(a) Technical Field of the Invention
The present invention relates to a mortise lock, and in particular to a mortise lock those allows for locking/unlocking with an outside lever or handle in order to ensure convenient and efficient operation of a door.
(b) Description of the Prior Art
An apartment or an access is often provided with a door with a locking device. The locking device includes a deadbolt, a latch bolt, and auxiliary latch bolt and often further comprise a locking latch that is operatively coupled to the auxiliary latch bolt so that normally the locking device can only be unlocked by an inside lever, but not an outside lever, unless a key is used. Thus, to ensure that one can unlock the door locking device from outside, one must secure the locking latch when the door is open to maintain the unlocked condition of the door locking device. This is to some extents troublesome to general users and is particularly true when a user, with no key with him or her, is locked outdoors by advertently closing the door. Under this situation, the user is kept from entering the door unless he or she has access to spare key.
Thus, it is desired to provide a mortise lock that allows a user to unlock from outside unless the lock is secured from inside so that the drawbacks and inconvenience occurring in the conventional mortise lock can be overcome.